Sealing and bearing device having low friction sealing faces



July 16, 1963 c. 5. WHITE 3,097,393

SEALING AND BEARING DEVICE HAVING LOW FRICTION SEALING FACES OriginalFiled Nov. 4, 1955 2 Sheets-Sheet 1 2 id 2 4 g) id 1 15.15. 41] lrauv INV EN TOR.

C'Zar/as j C. 5. WHITE July 16, 1963 SEALING AND BEARING DEVICE HAVINGLOW FRICTION SEALING FACES 2 Sheets-Sheet 2 Original Filed Nov. 4, 1955INVENTOR. 67147-788 -57 M/ZYZ'Z1Q United States Patent Ofi 3,097,893Patented July 16, 1963 ice 3,097,893 SEALING AND BEARING DEVICE HAVINGLOW FRICTION SEALHN G FAt'JES Charles S. White, Rte. 3, Box 454-H,Palmdale, Calif. Original application Nov. 4, 1955, Ser. No. 544,944,now

Patent No. 2,906,552, dated Sept. 29, 1959. Divided and this applicationAug. 11, 1959, Ser. No. 833,912

3 Claims. (Ci. 3083'6.2)

This invention relates to seals, bearings and pistons, and particularlyto seals, bearings and pistons having a low friction sealing facethereon, and is a division of copending application, Serial No. 544,944,filed on November 4, 1955, now Patent No. 2,906,552, issued September29, 1959.

The present invention particularly applies to seals, bearings andpistons for moving members having an engaging or working face which haslow friction characteristics. When employing the elastomeric materialsof the seal body for directly engaging the moving member, the employedpressure was high to prevent leaks, resulting in high friction and thedeterioration of the material of the seal body and damage to the surfaceof the engaged part.

The present invention pertains to the use of the low friction materialin fiber form, maintained in fixed position on the body material of theseal. Such fibers have a tensile strength substantially greater than thematerial when in sheet or block form, in some instances being as much astwenty-five times greater. The fibers may be uniformly distributed anddirectly engaged and bonded to the body material by cohesion or adhesiondirectly or by the use of a known bonding agent, depending on thematerial of the fibers and that of the body material. It was found thatthe fibers were more easily applied when woven in fabric form. Thus, aWoven fabric of nylon in flat and sleeve form is directly bondable tothe flat or annular working face of the rubber seal body. While nylonand other plastics have varying low friction properties and aredesirable because of their low cost, still others have much lowerfriction characteristics.

The bonding characteristics of the fibers of the plastic materialsappear to decrease as the friction characteristics decrease, so that themost desirable materials in fiber form completely lack bondingcharacteristics and are impossible to secure to the body material byknown bonding methods. To overcome this difliculty and permit the use ofthe most desirable plastic fibers having the lowest frictioncharacteristics, these fibers are Woven into a compound fabric having aWorking face of low friction fibers and a backing face of bondablefibers. Thus, the low friction face may be applied to a fabric having abondable back face, to the face of a webbing material if body is desiredback of the low friction face, or to the inner or outer side of a fabricin sleeve form, with the opposite side having the bendable face. Whennot subjected to high heat and pressure, fibers having higher frictioncharacteristics, which of themselves have bonding properties and whichare much lower in cost, as mentioned above, may be utilized and bondeddirectly to the body material. When the compound fabric is employed, thefibers are evenly disposed and adjacently supported so as to provide acontinuous surface on the backing layer which retains the fibers againstmovement when bonded to the body material.

Primarily the invention pertains to known types of seals to which fabricof low friction fibrous material is applied to the face which engagesthe moving part whether in rotation or reciprocation, or both. The bodyof the seal is preferably made of elastomeric material and the fabric isloose woven so that it will expand or contract with the material of thebody and be urged under pressure into sealing relation with the movingpart. The fabric may be in flat form when placed upon a flat surfacewhich is engaged by the end of a moving part, such as on a thrust washertype of seal, and is in the form of a sleeve when secured to the inneror outer annular surface or to both the inner and outer annular surfaceof the seal. When the low friction type of fibers are employed which donot readily bond to the elastomeric material of the body, then thefabric is of the compound type above mentioned which is morespecifically illustrated, described and claimed in the copendingapplication of C. S. White, Serial No. 544,945, filed November 4, 1955,for Low Friction Fabric Material, and now Patent No. 2,804,886, issuedon September 3, 1957.

Accordingly, the main objects of the invention are: To provide a sealwhich effectively withstands the high speed operation of the engagedpart in the presence of high pressures which maintain a sealingengagement; to provide a layer on the face of a seal body which engagesthe operating part with the layer having low friction characteristicsand which is integrally bonded to the material forming the body of theseal; to bond a fabric made of fibers having low frictioncharacteristics to the engaging portion of a seal in unit relationthereto, and,

in general, to form a seal having an engaging face of low frictioncharacteristics which is simple in construction, positive in operation,and economical of manufacture.

Other objects and features of novelty of the invention will bespecifically pointed out or will become apparent when referring, for abetter understanding of the invention, to the following descriptiontaken in conjunction with theacc-ompanying drawings, wherein:

FIGURE 1 is a plan view of an O-ring having a face thereon of lowfriction material embodying features of the present invention;

FIG. 2 is an enlarged sectional view of an O-ring similar to thatillustrated in FIG. 1, having the outer engaging face thereof bonded toa low friction fabric;

FIG. 3 is a view of structure, similar to that illustrated in FIG. 1,with the low friction fabric secured to the inner working face thereof;

FIG. 4 is a view of structure similarly illustrated in FIG. 2, with thelow friction fabric bonded to the entire face thereof;

FIG. 5 is a view of an annular sealing ring which is U shape in crosssection having the inner face thereof bonded to a fabric having lowfriction characteristics;

FIG. 6 is a view of structure similarly illustrated in FIG. 5 showingthe fabric having low friction characteristics bonded to both facesthereof;

FIG. 7 is a view of structure similarly illustrated in FIG. 5, showingthe low friction fabric material bonded to the outer face thereof;

FIG. 8 is a view of a cup-shaped seal having a low friction fabricmaterial bonded to the outer peripheral face thereof;

FIG. 9 is a View of a V-shape type of seal having the low frictionfabric material bonded to the outer engaging face thereof;

FIG. is a view of a washer-like seal having the working face thereofbonded to the low friction fabric material;

FIG. 11 is a view of a cylindrical seal having a sleeve of the lowfriction fabric material bonded on the inner face thereof;

FIG. 12 is a view of an annular seal which is L shape in section, havingon the inner working face a low friction fabric material bonded thereto;

FIG. 13 is a sectional view of a washer-like seal having the lowfriction fabric material bonded to the inner engaging face thereof;

FIG. 14 is a view of a seal similarly illustrated in FIG. 13, in whichthe body of the seal is recessed to provide more resiliency to theworking face thereof;

FIG. 15 is a view of a seal similarly illustrated in FIG. 14, having thebody offset to provide greater width to the working face having the lowfriction material bonded thereto;

FIG. 16 is a view of a seal similarly illustrated in FIG. 12, having onthe engaging face thereof the low friction material;

FIG. 17 is a sectional view of a cylindrical type hearing and sealhaving on the entire inner face thereof a sleeve of low frictionmaterial which is bonded to the elastomeric body material;

FIG. 18 is a View of structure, similar to the illustrated in FIG. 17,with the bearing portion applied to the outer surface of a piston;

FIG. 19 is a plan view of a fabric having a face of low frictionmaterial and a face of bondable cords on opposite sides thereof, and

FIG. 20 is an enlarged sectional view of the structure illustrated inFIG. 19, taken on the line 20-20 thereof.

A large number of well known seals are herein illustrated by way ofexample, to which the low friction fabric material has been bonded in amanner embodying the present invention. While the large number of sealshave been shown for the purpose of disclosing the differentapplications, it is to be understood that such showing is not to beconsidered limiting since there are many other types of seals to whichthe present invention applies.

In FIGS. 1-4, O-rings are illustrated having on the working face whichengages the moving surface a layer of the low friction fabric materialwhich is bonded thereto. In FIG. 2 and O-ring 20 of the scalloped typehas on the outer face a layer of woven fabric material 21 which has lowfriction characteristics. As pointed out hereinabove, such material maybe woven from fibers of rayon, nylon, vinyl and the like resins, whichare known for their comparatively low friction properties and which bondto the elastomeric body material of O-ring or other types of seals. Sucha material on the surface of the O-ring substantially increases the lifethereof by reducing the friction between the O-ring and the relativelymovable surface. Under low speed and low friction application, suchmaterials operate satisfactorily; however, under high loads and highpressure conditions, the material of the fabric 21 is preferably Teflonor other fluorocarbon material having a backing of cords which bonds tothe body material and which is described and claimed in the abovementioned copending application. In FIGS. 19 and 20, the fabric materialhas a layer of low friction fiber threads 80 forming the warp of thefabric while low friction threads 81 form the filler thereof. Bondablecords 82 are disposed parallel to the warp threads 80 and are retainedby having each of the filler threads 81 pick up a bondable cord 82 atcertain spaced points, herein illustrated as at every fourth cord. Thenext adjacent filler thread 81 picks up the next adjacent bondable cord82 and skips three of the adjacent bondable cords before picking up thenext adjacent cord 82. In

this manner, the working face of the resulting material will be entirelyof the low friction threads while the rear bondable face will have thegreatest part thereof formed of the bondable cords 82. The bondablecords, therefore, will form anchor areas for the face of the lowfriction threads and the low friction threads will form a nonfrictionsurface.

In FIG. 3 an O-ring 20' is illustrated having on the inner working facethereof a low friction fabric material 23 which is bonded to theelastomeric body material. In FIG. 4 an O-ring 24 is illustrated havingthe entire surface encased by a fabric sleeve of the herein defined typewhich embodies low friction characteristics. 'In such an arrangement anypart of the outer surface of the 0- ring may operate against a movingsurface in a manner to substantially increase the life of the O-ring. Itis to be understood that the low friction material bonds to theelastomeric material of the body in a manner to have the surface thereoffree from the material so that the entire engaging surface has the lowfriction properties. Further, a flexible weave is preferably employed inthe fabric or sleeve such as that employed in hosiery which is so wovenas to enable the hosiery to expand to the contour of a persons leg eventhough the individual threads of the hosiery are not elastic. Suchweaves are well known in the art and in the present invention provide alow friction engaging surface which is extremely flexible so that thepressure exerted by the elastomeric material of the body will in no waybe affected thereby.

In FIG. 5, a seal 26 is illustrated of the U-shape type having a web 27and an outer cylindrical flange 28 and an inner cylindrical flange 29.The sealing face of the inner flange 29 has the low friction fabric 30bonded thereto either directly or by an adhesive material or by abacking layer secured thereto which is bonded to the flange 29. Thefabric material is preferably woven in a sleeve form so as to becontinuous when applied to the sealing face of the flange 29 and ispreferably of an elastic weave, such as in hosiery, so that it mayexpand and contract with the flange 29. A similar construction isillustrated in FIG. 6 wherein the annular U-shaped seal has the wovenfabric material applied to both the inner and outer faces, that is tosay, on the faces of the flanges 28 and 29. In FIG. 7 a simular U-shapedtype of annular seal is illustrated, wherein the outer sealing face onthe flange 28 has the low friction fiber fabric material bonded thereto,as explained above.

In FIG. 8 a cup-shaped type of seal 31 is illustrated, having an annularflange 32, the outer sealing face of which has the low friction fabricmaterial 33 bonded thereto in the manner as pointed out hereinabove,that is to say, the fabric material is preferably woven in sleeve formwith a hosiery type weave so that the sleeve may expand and contractwith the expansion and contraction of the flange 32.

FIG. 9 illustrates a V type of seal 34 which may be employed singly orin multiples and which has a working face on the inner or outer edges 35and 36. Either or both of these edges has the fabric material 37 bondedthereto, the material preferably being in a woven sleeve form of ahosiery-like elastic weave to permit the face or faces to expand withthe material of the seal.

In FIG. 10 a thrust washer 38 is illustrated having a washer-like body39 to the face 40 of which a washerlike fabric 41 of low friction fibermaterial is bonded. The fabric may be directly bonded to the material ofthe washer 39 or may be woven on a bondable layer which is secured tothe face of the body.

In FIG. 11 a sleeve type of seal 42 is illustrated, having a cylindricalbody 43 the inner surface of which has the low friction fabric 44secured thereto. The low friction fabric material in sleeve formpreferably has an elastic hosiery type of weave so that it will notrestrict the pressure exerted by the cylindrical body portion 43 of theseal and may have a bondable face, as explained above.

In FIG. 12 a washer-like seal 45 is illustrated having an intumedcylindrical lip 46 with a sleeve of fabric material 47 in fabric orcompound fabric form bonded to the sealing face in a manner pointed outhereinabove. About the outer surface of the cylindrical sealing portion'46, a garter spring 48 may be applied for exerting pressure upon thebody 46 and urging the low friction material 47 of the sleeve intoengagement with an element being sealed thereby.

In FIG. 13 a washer-like seal 49 is illustrated having an offset sealingface 51 which has a sleeve of low friction fabric or compound fabricmaterial 52 bonded thereto. In FIG. 14 a similar seal 53 is illustratedhaving a body 54 and an inner sealing face 55 against which a sleeve 56of low friction fabric or compound fabric ma terial is bonded. Anannular groove 57 may be provided in the face of the body 54 to reducethe tension on the adjacent portion of the low friction sealing material56. A similar seal 58 is illustrated in FIG. 15 having a sealing face 59and a sleeve of low friction fabric or compound fabric material 61bonded thereto. The body 58 is stepped so that the upper portion willexert less pressure on the adjacent portion of the sleeve 61.

In FIG. 16 a further form of seal is illustrated, that having thecylindrical sealing portion 62 extending from a metal ring '63 andhaving a sleeve of low friction fabric or compound fabric material 64bonded to the inner sealing face thereof. The sleeve is preferably wovenwith an elastic hosiery weave so that it will expand to the shape of theworking face and offer no resistance to the contraction or expansion ofthe annular sealing portion 62.

For applying a pressure to the sealing portion and the low frictionsleeve 64, a garter spring 65 is provided on the outer side of thesealing body.

In FIG. 17 a further form of the invention is illustrated, that whereina cylindrical body 66 preferably of elastomeric material forming -ahearing has a seal portion 67 on one end which is reduced in thicknessand which has pressure applied thereto by an annular garter spring 68.The sealing surface on the portion 67 and the bearing portion 66 has asleeve 69 of low friction woven material bonded to the inner facethereof. The sleeve is preferably woven with an elastic hosiery weave sothat it may cover the faces of the seal and bearing and permit the sealand bearing portions to contract into bearing and sealing relation to arod or shaft extending therethrough. Not only is a seal provided at oneend of the hearing but the bearing portion itself permits vibration anda slight play of the shaft portion engaged thereby while providing adesirable bearing engagement with the surface thereof.

Referring to FIG. 18, a further embodiment of the present invention isillustrated, that provided by applying the low friction material to theouter surface of a piston. A piston 71 has a sleeve 72 of elastomericmaterial secured thereto, with the outer surface 73 of the low frictionfiber material. The elastomeric material may be in solid cylindricalform, eliminating the piston 71, or the piston may have the low frictionfiber material 73 directly secured thereto. The elastomeric materialpermits slight misalignment of the rod and cylinder and provides lateralpressure to form a desirable seal with the cylinder surface. It is to beunderstood that a seal face may be provided on one or both ends of thesleeve 72 similar to the seal 67 on the bearing 66 of FIG. 17 or suchseal faces may be omitted from both of the embodiments.

Various types of seals have been illustrated and described herein toshow the different applications of the low friction fabric material tothe sealing faces of the seals and the face of the bearing and pistonhaving the elastomeric body. It has been clearly pointed out that thefabric material has low friction characteristics and is secured to thesealing face of the seal and also on the face of the bearing. In certaininstances the fibers of the fabric will directly bond to the material ormay be supported by cords or fibers which will bond thereto. The weaveof the fabric when employed on the elastomeric body material ispreferably of the flexible hosiery type so that it offers no resistanceto the pressure exerted by the elastomeric material. Preferably theweave is uniform in all directions but when providing a unidirectionalstructure the unidirectional position of the weave follows the directionof the movement of the element which is sealed to provide the best lowfriction engagement therebetween.

The application of the tetrafiuoroethylene material to the entiresurface of the seal, bearing, piston and the like, as illustrated inFIG. 4, may be made to any type of seal, bearing or piston, those hereinillustrated and others on which such materials may be applied. Byenclosing the articles with the tightly woven tetrafluoroethylenematerial which withstands high temperatures, the body material will beretained within the woven fiber material even though it should softenunder heat. In a large number of cases, when the body material has againcooled, it will assume its original shape and be as effective as beforeto perform as originally intended. Since the tetrafiuoroethylenematerial is substantially insoluble, the seals, bearings ,and pistonsenclosed by the tightly woven fibers thereof will prevent any fluids orother materials from contacting the body material 'which will not beharmed in the presence of such fluids or other materials. Therefore,when the seals, bearings and pistons have the body material completelyenclosed by the tetrafluoroethylene fabric material, the seals, pistonsand bearings will be substantially indestructible when operated in thepresence of fluids or materials which would damage the body material. Itis, therefore, to be understood that the application of the fabric tothe surface of the O-ring, as illustrated in FIG. 4, is not to beconsidered limiting but such application can be made to all seals,pistons and bearings, those herein illustrated as Well as others knownin the art. The elastomeric material of the body is inserted within theenclosing fabric of tetrafluoroethylene material by needles which arepunched through the layer of the fabric into the interior thereof. Apredetermined amount of elastomeric material is injected into theinterior encompassing fabric and thereafter the material and fabric aremolded to a desired form in any known manner, such as in a set of dies.

What is claimed is:

1. A combination bearing and seal for a shaft comprising a bushing madeof elastomeric material, a low friction clothlike material havingpolytetrafluoroethylene filaments therein on the inner surface of saidbushing adapted to slidably engage the shaft to provide a bearingsurface therefor, and a resilient element encircling one end of saidbushing for continuously exerting a resilient radially inward forcethereon to form a seal with said shaft.

2. A combination bearing and seal for a shaft comprising a bushing madeof elastomeric material, a low friction clothlike material on the innersurface of said bushing adapted to slidably engage the shaft to providea bearing surface therefor, and a resilient element encircling one endof said bushing for continuously exerting a resilient radially inwardforce thereon to form a seal with said shaft, said low friction materialbeing a fabric having polytetrafiuoroethylene fibers on one face thereofand bondable fibers on the other face thereof, said bondable fibersbeing bonded to the inner surface of said bushing to mechanically retainthe polytetrafluoroethylene fibers in position to engage the shaft.

3. A low friction element comprising an annular layer of elastomericmaterial, a layer of bondable clothlike material having filaments ofnonbondable polytetrafluoroethylene therein with the clothlike materialbonded to a surface of said elastomeric material to provide a lowfriction surface for said element which is to contact a surface of amember, said clothlike material having an 7 expansible Weave to permitthe nonbondable filaments to expand and contract with the layer ofelastomeric material which urges the nonbondable filaments into intimateengagement with said surface.

References Cited in the file of this patent UNITED STATES PATENTS2,240,332 Heinze et a1. Apr. 29, 1941 Booth -4 Feb. 15, 1949 Waring Mar.29, 1955 Hetherington Sept. 6, 1955 Fagg et a1. Oct. 2, 1956 HerbenarJan. 22, 1957 Stallings Aug. 27, 1957 Bowtempi Feb. 25, 1958 ConnollyApr. 7, 1959

1. A COMBINATION BEARING AND SEAL FOR A SHAFT COM-